In the above example, the person did a 24 hour halide urine test and then followed up with a 24 hour haline urine test with a 50mg Iodine load. Excretion of Iodine was ~93%, but bromide and flouride decreased a little in the test. A level of 10mg/L of serum bromine concentration interferes with Iodine utilization as well. Serum bromine is usually twice the urine concentration.
In another case example in the link, the post-24 hour loading of Iodine test revealed that significantly more fluoride was excreted later.